Inhibitory neuron migration and IPL formation in the developing zebrafish retina.
Bottom Line: All RINs then transition to a less directionally persistent multipolar phase of migration.Finally, HCs, iACs and dACs each undergo cell type-specific migration.In contrast to current hypotheses, we find that most dACs send processes into the forming inner plexiform layer (IPL) before migrating through it and inverting their polarity.
Affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK.Show MeSH
Mentions: To visualize RIN migration, we made use of a transgenic zebrafish line in which the promoter of the gene that encodes the basic helix-loop-helix (bHLH) transcription factor Ptf1a drives the expression of DsRed in RINs (Jusuf and Harris, 2009). This allowed us to follow several Ptf1a+ cells located in apical parts of the retina (Fig. 1A; supplementary material Movie 1). All of these cells exhibited elongated bipolar morphologies as they migrated basally towards the centre of the retina (Fig. 1A, 0 min). Moreover, it became clear that most of these cells retracted their apical processes only after they reached the middle of the retina (Fig. 1A, 150 min). Multipolar Ptf1a+ cells in the apical part of the INL (i.e. HCs) became apparent only later (Fig. 1A, 540 min). These observations suggested that many RINs begin their migration in a bipolar mode before switching to a multipolar morphology.Fig. 1.
Affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK.